Baseball pitchers commonly use an exercise known as “throw the towel” to improve the follow-through of their delivery. In this exercise, a small hand towel is knotted at one end, and the pitcher grips the knotted end in his/her pitching hand as if it were a baseball. The pitcher then completes his/her delivery without releasing the towel. Audible “snapping” of the unknotted end of the towel at the completion of the pitcher's delivery is indicative of a full follow-through and efficient pitching mechanics. In addition to providing feedback to improve pitching mechanics, the “throw the towel” exercise also provides resistive training for arm muscles and increases arm speed.
But the conventional “throw the towel” exercise falls short of simulating an actual pitcher's delivery in several respects. The towel knot does not have the size, shape or weight of an official baseball, nor does it have a baseball's seams, by which the pitcher's fingers grip the ball. Moreover, because the knot cannot move independently of the entire towel, the ability of the pitcher's hand to rotate as he/she completes his/her delivery is severely constrained. The lack of seams on the towel knot also prevents the trainee pitcher from practicing different grips associated with various pitches, such “four-seam” and “two-seam” fastballs, change-ups and assorted breaking pitches.